Torque-Sensing Therapy Actuator for Closed-Loop Load Control

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Solution Overview

Problem

Current robotic therapy devices for neurological and neuromuscular disorders lack appropriate actuator designs and sensing capabilities, limiting their effectiveness in rehabilitation settings, and existing devices often exert unintended forces due to lack of torque sensing.

Innovation Solution

A torque sensing actuator design with integrated force measurement and feedback capabilities, allowing for active sensing and customization to individual patient progress, and enabling accurate load measurement and closed-loop torque control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If robotic therapy devices are used for neurological and neuromuscular disorders, then rehabilitation therapy can be provided, but the devices lack appropriate actuator designs and sensing capabilities which limits their effectiveness

Engineering Contradiction:
Improveeffectiveness of rehabilitation therapyVSAvoidactuator design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the actuator and torque sensor into a single integrated unit. The torque sensor is mounted directly on the actuator shaft, allowing simultaneous measurement of torque and actuation functions. This merging resolves the contradiction by achieving reliable rehabilitation therapy through integrated sensing and actuation without proportionally increasing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The actuator design incorporates multiple functions: motor-driven rotation, torque sensing, and feedback control capabilities. The same actuator structure serves both as the actuation mechanism and as the mounting platform for torque sensing, providing multi-functionality that improves rehabilitation effectiveness without requiring separate dedicated components for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If existing robotic devices are used without torque sensing, then device complexity is reduced, but the devices exert unintended forces due to lack of torque sensing

Engineering Contradiction:
Improvecontrol accuracyVSAvoidsensing capability complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements closed-loop feedback control by mounting a torque sensor on the actuator shaft that provides real-time torque measurements back to the control system. This feedback enables the controller to adjust actuation commands to prevent unintended forces, resolving the contradiction between control accuracy and device complexity through intelligent control rather than overly complex hardware.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces complex mechanical force control mechanisms with a combination of torque sensing and electronic feedback control. Instead of using complex mechanical systems to prevent unintended forces, the solution uses electronic sensing and control algorithms to achieve precise force control, reducing mechanical complexity while improving reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If robotic exoskeletons are applied for stroke treatment, then recovery process can be accelerated, but the devices lack personalized therapy capabilities

Engineering Contradiction:
Improvepersonalization of therapyVSAvoidsensing and feedback system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The torque sensor mounted on the actuator shaft provides real-time feedback on patient resistance and effort during therapy exercises. This feedback enables the control system to adapt therapy parameters in real-time based on patient response, allowing personalized therapy that adjusts to individual patient progress without requiring overly complex sensing systems.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The actuator system with integrated torque sensing enables the device to automatically adjust therapy delivery based on real-time patient response. The system serves itself by using its own torque measurements to modulate actuation, eliminating the need for external manual adjustment mechanisms and reducing overall system complexity while providing personalized therapy.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3927496B1Actuator for physical therapy
Publication Date: 2025.12.10 BIONESS MEDICAL INC
  • EP3927496B1 patent drawingFigure 1
  • EP3927496B1 patent drawingFigure 2
  • EP3927496B1 patent drawingFigure 3

AI summary

An embodiment includes a robotic system comprising: a joint coupling a linkage to an additional linkage; and at least one cable; wherein the joint includes a motor having a shaft, a strain wave gear having a flexible member coupled to a circular spline, a conduit, and a bearing; wherein the motor is configured to rotate the shaft in a first direction and the strain wave gear is configured to rotate a rotatable member, 5 the rotatable member including one of the flexible member or the circular spline; wherein the conduit is configured to rotate in response to rotation of the rotatable member; wherein the at least one cable passes through both the bearing and into the additional linkage but does not pass through either of the strain wave gear or the motor.